1~2* AA/AAA 5-Mode 800mA Linear Booster LED Flashlight Driver Circuit
Driver is from Fasttech.com
- 0.9V~3.6V / 500mA@1.5V / 800mA@3.6V / 17mm
- Constant Current: Yes
- Driver Type: Boost driver and Linear regulator
- Input Voltage: 0.9~3.6 -volt
- Output Current: 800 mA
- PCB Height (w/o Components): 1.5 mm
- Reverse Polarity Protection : No
- Flashlight Modes: Hi > Mid > Lo > Strobe > SOS
- Mode Count: 5
- Mode Memory: No
- Depth: 2 mm
- Diameter: 17 mm
- Product Weight: 1.1 g
- Booster driver mode when input voltage is 1.5V or less
- Linear regular (constant current) mode when voltage is between 1.8V and 3.6V
- Rated at 500mA current output @ 1.5V input
- Rated at 800mA current output @ 3.6V input
Tested with: Cree XP-G2
Driver diameter 16.8mm
Driver height 5mm
The driver uses boost mode and will be forced into direct drive when voltage is to high.
The driver has high, medium, low, strobe and sos.
No memory, always starts in high.
A short off/on will select next mode.
Medium pwm 550Hz with 40% duty cycle
Low pwm 560Hz with 15% duty cycle
Strobe 7.6Hz with 50% duty cycle
Below 1.5 volt the driver will try to draw a constant current from the battery.
When 1.5 volt is reached the brightness is stabilized, until the voltage reaches Vf of the led.
Above Vf of the led the driver will be in direct drive mode.
At low voltage the efficiency is low (as always) and a lot of power is lost in the driver.
When the driver stabilizes its output, the power loss goes down, as the current goes down.
Starting from 0 volt, the driver turns on at 0.75 volt.
In high mode there is no pwm in the light and only a small amount of high frequency noise.
Because the driver uses pwm, the shape of this curve looks very much like high mode (With pwm the led is driven at full power, but not all the time).
Pwm is at 550Hz.
Low mode is also the same, but at even lower currents.
Pwm is at around 560Hz.
Strobe is at 7.6 Hz. Brightness is at full.
Brightness is at full.
The driver looks like a good driver for one or two NiMH batteries or a CR123 battery, but cannot safely be used with LiIon.
With one NiMH battery the voltage will be too low to stabilize brightness.
With a maximum current draw of about 2A it is not really a good driver for alkaline batteries.
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